#1.in,判断某个成员是否在数组内
books = ["三国","西游","红楼"]
a = ("三国" in books)
print(a) #True

#2.not in,字面意思

#3.count(),找下在哪个位置，找到返回从左到右（1到无穷），找不到返回0
books = ["三国","西游","红楼"]
b = books.count("三国")
c = books.count("水浒")
print(b) #1
print(c) #0

#4.index()，找不到报错，找到返回下标
d = books.index("水浒传")
print(d)






